全文获取类型
收费全文 | 9332篇 |
免费 | 949篇 |
国内免费 | 36篇 |
专业分类
耳鼻咽喉 | 116篇 |
儿科学 | 306篇 |
妇产科学 | 273篇 |
基础医学 | 1390篇 |
口腔科学 | 236篇 |
临床医学 | 983篇 |
内科学 | 1852篇 |
皮肤病学 | 66篇 |
神经病学 | 854篇 |
特种医学 | 302篇 |
外科学 | 1311篇 |
综合类 | 202篇 |
一般理论 | 5篇 |
预防医学 | 766篇 |
眼科学 | 463篇 |
药学 | 682篇 |
中国医学 | 12篇 |
肿瘤学 | 498篇 |
出版年
2023年 | 38篇 |
2021年 | 187篇 |
2020年 | 112篇 |
2019年 | 189篇 |
2018年 | 192篇 |
2017年 | 145篇 |
2016年 | 163篇 |
2015年 | 196篇 |
2014年 | 260篇 |
2013年 | 352篇 |
2012年 | 539篇 |
2011年 | 632篇 |
2010年 | 341篇 |
2009年 | 297篇 |
2008年 | 571篇 |
2007年 | 625篇 |
2006年 | 576篇 |
2005年 | 518篇 |
2004年 | 571篇 |
2003年 | 449篇 |
2002年 | 438篇 |
2001年 | 114篇 |
2000年 | 124篇 |
1999年 | 131篇 |
1998年 | 106篇 |
1997年 | 98篇 |
1996年 | 83篇 |
1995年 | 74篇 |
1994年 | 90篇 |
1993年 | 65篇 |
1992年 | 87篇 |
1991年 | 76篇 |
1990年 | 55篇 |
1989年 | 69篇 |
1988年 | 59篇 |
1987年 | 63篇 |
1986年 | 79篇 |
1985年 | 96篇 |
1984年 | 61篇 |
1983年 | 60篇 |
1982年 | 75篇 |
1981年 | 77篇 |
1980年 | 59篇 |
1979年 | 65篇 |
1978年 | 58篇 |
1977年 | 51篇 |
1976年 | 40篇 |
1974年 | 43篇 |
1973年 | 40篇 |
1972年 | 45篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
Gary A Noskin Robert J Rubin Jerome J Schentag Jan Kluytmans Edwin C Hedblom Cassie Jacobson Maartje Smulders Eric Gemmen Murtuza Bharmal 《Clinical infectious diseases》2007,45(9):1132-1140
BACKGROUND: We evaluated historical trends in the Staphylococcus aureus infection rate, economic burden, and mortality in US hospitals from 1998 through 2003. METHODS: The Nationwide Inpatient Sample was used to assess trends over time of S. aureus infection during 1998-2003. Historical trends were determined for 5 strata of hospital stays, including all inpatient stays, surgical procedure stays, invasive cardiovascular surgical stays, invasive orthopedic surgical stays, and invasive neurosurgical stays. RESULTS: During the 6-year study period from 1998 through 2003, the rate of S. aureus infection increased significantly for all inpatient stays (from 0.74% to 1.0%; annual percentage change (APC), 7.1%; P=.004), surgical stays (from 0.90% to 1.3%; APC, 7.9%; P=.001), and invasive orthopedic surgical stays (from 1.2% to 1.8%; APC, 9.3%; P<.001). For invasive neurosurgical stays, the rate of S. aureus infection did not change from 1998 to 2000 but increased at an annual rate of 11.0% from 2000 to 2003 (from 1.4% to 1.8%; P=.034). The total economic burden of S. aureus infection for hospitals also increased significantly for all stay types, with the annual percentage increase ranging from 9.2% to 17.9% (P<.05 for all). In 2003, the total economic burden of S. aureus infection was estimated to be $14.5 billion for all inpatient stays and $12.3 billion for surgical patient stays. However, there were significant decreases in the risk of S. aureus-related in-hospital mortality from 1998 to 2003 for all inpatient stays (from 7.1% to 5.6%; APC, -4.6%; P=.001) and for surgical stays (from 7.1% to 5.5%; APC, -4.6%; P=.002). CONCLUSIONS: The inpatient S. aureus infection rate and economic burden of S. aureus infections for US hospitals increased substantially from 1998 to 2003, whereas the in-hospital mortality rate decreased. 相似文献
42.
David M. Dickinson Dawn M. Dykstra Gregory N. Levine Shiqian Li James C. Welch Randall L. Webb 《American journal of transplantation》2005,5(4P2):850-861
The process of collecting and analyzing transplant data is complex. Familiarity with how these data are collected is crucial to a thorough understanding of the information. This article focuses on available OPTN-SRTR data and the continuing evolution of data collection mechanisms; how that data collection system is improving the data quality and reducing the data collection burden; how additional ascertainment of outcomes both completes and validates existing data; and caveats that remain for researchers. This year's article focuses further on research considerations related to cohort choice, timing of data submission, and potential biases in follow-up data. Ongoing improvements in data collection timeliness and scope are covered. The impact of extra ascertainment of outcomes, particularly for post-transplant kidney graft failure from Medicare data, are also examined. A section on graft failure reporting among different sources traces the steps by which the SRTR reconciles different data sources in its analyses. It is important that those reading and conducting transplant research understand the origin, structure, and scope of the available data. All of these issues should be carefully considered when choosing cohorts and data sources for analysis. 相似文献
43.
44.
45.
46.
Alberto Salinas M.D. Harry M. Salinas B.Sc. Edwin Santiago Ph.D. Wilfredo García M.D. Queta Ferro R.D. Mariemma Antor M.Sc. 《Surgery for obesity and related diseases》2009,5(4):455-458
BackgroundSilastic ring vertical gastric bypass (SRVGB) with jejunal interposition is our standard operation for morbidly obese patients. We present the results of 5 years of follow-up in a cohort of patients who underwent SRVGB in 2001.MethodsThe records of all 160 consecutive patients who underwent SRVGB from January to December 2001 were reviewed. Of the 160 procedures, 143 were primary open cases, 14 were revisions from restrictive procedures, and 3 were laparoscopic cases. At 5 years, the body mass index and percentage of excess weight loss was available for 133 patients (83%) at office visits (n = 91, 68.4%), by telephone (n = 40, 30.1%), or by e-mail (n = 2, 1.5%).ResultsOf the 160 patients, 121 were women and 39 were men, with a mean age of 33.15 ± 10.0 years, percentage of ideal body weight of 195.7% ± 40.8%, and body mass index of 44.6 ± 9.3 kg/m2. The mean hospital stay was 3 ± 1 days. One patient (.6%) died of a pulmonary embolus. Early complications included 3 cases (1.87%) of upper gastrointestinal bleeding and 4 gastric leaks (2.5%): 2 (1.36%) from primary cases and 2 (14.29%) from revisional cases. Late complications included 32 patients (20%) with incisional hernias, 20 (12.5%) with anemia, 14 (8.8%) with dumping, 4 (2.5%) with gastrojejunal stricture, 2 (1.25%) with intestinal obstruction, and 2 (1.25%) requiring silastic ring surgical removal. The 5-year follow-up data were available for 133 patients (83%). The mean body mass index in this group was 27 ± 5 kg/m2, with a percentage of excess weight loss of 83% ± 18.3% at 5 years postoperatively.ConclusionThe results of our study have shown that SRVGB is an effective operation for promoting lasting weight loss, with acceptable mortality and complication rates. 相似文献
47.
48.
Lynn McIntyre Edwin G. Belzer Lise Manchester Wade Blanchard Suzanne Officer A. Catherine Simpson 《The Journal of school health》1996,66(3):132-137
ABSTRACT: The Dartmouth Health Promotion Study was a longitudinal, quasi-experimental field study with a qualitative research arm, designed to learn whether coordinating school health instruction, health services, and a healthful environment enhanced the program's effect on the heart health and mental health of children. The research strategy — the Coordinated Approach — was applied to approximately 300 children in each of two cohorts in grades four to six attending nine trial schools; a further 600 children attended 10 comparison schools in Dartmouth and nine distal comparison schools. Although the qualitative analysis demonstrated that positive feelings were engendered in most areas of the study, when either the classroom or the individual was used as the unit of analysis, the Coordinated Approach did not have a more favorable effect on the heart or mental health of children than did the standard school health program. Thus, the effect of an existing school health program was not directly enhanced through coordinating its components. 相似文献
49.
Six patients with prolonged acute courses of thrombotic microangiopathy are reviewed. These patients had in common courses of acute disease requiring plasma support for more than 3 months, with subsequent complete remission. Plasma support requirements may be prodigious, and the acute course may require more than 100 plasma exchanges before a stable remission is achieved. These patients appear to represent a subset of thrombotic microangiopathy distinct from the more common acute T.T.P. course, which resolves in 3–6 weeks, and the chronic relapsing pattern, which may have a short or prolonged acute course. © 1992 Wiley-Liss, Inc. 相似文献
50.
OBJECTIVE: To investigate whether the sex ratio of children varies between fathers of different occupations. METHODS: The sex ratio (the ratio of the number of boys to the number of girls at birth) was calculated in relation to paternal occupation in the cohort of all 253,433 live births in Cumbria, north west England, from 1950-89. Exact binomial confidence intervals were used to estimate whether the sex ratio in each occupational category was significantly different from that for the rest of the cohort. RESULTS: There were fewer occupational categories with significantly different sex ratios at the 5% level than expected by chance alone, assuming the same binomial distribution of sexes at birth within each paternal occupation. CONCLUSIONS: Significant variation of the sex ratio with fathers' occupations was not found. There is some evidence that the sex ratio shows less variance than expected under a binomial model which assumes independence of the sex of each child; a possible explanation of this may be parental preference for limiting family size after children of both sexes have been born or some other factor which results in children within a family being more likely to be of both sexes rather than the same sex. 相似文献